The present invention relates to electrical switches. More particularly, the invention relates to a multi-position electrical switch for use in the remote control of a rearview mirror of a motor vehicle.
Each of the two outside rearview mirrors of a motor vehicle is provided with two electric motors and a driving transmission in a mirror body, and the angle of inclination of the respective rearview mirrors is remotely controlled by means of a control switch arranged in a compartment of the motor vehicle so as to adjust the horizontal inclination in rightward or leftward direction and the vertical inclination in upward or downward direction. Known are two construction types of such a control switch. In one construction, as disclosed in U.S. Pat. No. 4,349,708, a joystick is projected at the top of a casing, the joystick is rotatably supported by spherical supporting means in the casing, movable- and stationary contact groups are disposed at the circumference of a lower portion of the joystick, and the selected contacts are closed by the actuation of the joystick to control the normal or reverse rotation of the electric motor or to stop the same. However, in this type, in order to reliably open or close the contacts, a return spring must be attached to the joystick. Consequently, the overall configuration of the switch cannot be sufficiently reduced in size, and the large number of components increase manufacturing cost.
The other known type includes a printed circuit (PC) board supporting a motor control circuit, a compressible conductive rubber sheet superposed on the PC board, and a seesaw type knob tiltable in four directions for switching the contacts on the PC board by pressing the conductive rubber sheet.
When the knob is tilted in a vertical or horizontal direction, the conductive rubber sheet at the position corresponding to the selected direction is pressed to close the corresponding contacts on the PC board, and the angle of inclination of the mirror element is adjusted by rotating the motor in a forward or reverse direction.
However, in the switch of the latter type, the operator may accidentally actuate several contacts simultaneously, thus causing an electric shortcircuit therebetween and the mirror driving motor may become damaged. Similarly, when the knob is pushed in the intended direction, the contact adjacent to the intended contact can be also simultaneously contacted and the reliability of the switching operation is impaired. To eliminate such drawbacks, in the U.S. Pat. No. 4,476,356, a rod-like or crest-sectional projection is used to act as a fulcrum at the center of the lower surface of the seesaw-type knob body to maintain an insulating distance between the movable contact and the corresponding stationary contact, but even this design cannot always solve all the above-mentioned problems.